That was the question being asked around the Chinese Internet on Monday, after Mr. Xi appeared over the weekend wearing a finely tailored modern take on the traditional Mao suit, at a dinner hosted by the king of the Netherlands.

Mr. Xi, on the first state visit by a Chinese president to the Netherlands, is in the country along with other world leaders for a nuclear-security summit in The Hague.

Chinese President Xi Jinping wearing a modern take on the traditional Mao suit at the Royal Palace in Amsterdam.

European Pressphoto Agency

The state-run China Daily said the choice of the suit by Mr. Xi “displayed the leader’s national pride and confidence in Chinese culture.” Mr. Xi normally appears in standard black suits and solid-colored ties.

“Foreigners will interpret the [suit] as a political symbol because it has typical Chinese connotations,” He Yang, an associate professor at the Beijing Institute of Fashion Technology, told China Daily.

The suits—known as Mao suits in the West because they were popularized during the reign of Mao Zedong–were actually first worn as early as the 1920s. In Chinese, the outfits are called zhongshan zhuang, or Yat-sen suit, named instead after China’s first president, Sun Yat-sen.

Since China began opening up and interacting more with the outside world in the 1980s, most leaders have set aside their old gray Chinese threads in favor of Western-style suits and ties, though they are still often worn for special occasions. In a 2009 celebration of the 60th anniversary of the country’s founding, China’s previous president, Hu Jintao, wore a traditional gray Mao suit at an inspection of the country’s military in Tiananmen Square.

“The style accompanying the first couple’s appearance is heavy with Chinese resonances,” one verified user wrote. “Leaders who attend formal events in the future can also wear Chinese dress, not only to avoid faux pas but also to present charm and elegance, and even more so to effectively promote traditional Chinese culture.”

“By wearing this suit, Mr. Xi is displaying a self-confidence and respect for Chinese traditions,” another user wrote.

Many noted that Mr. Xi’s suit had some differences from the traditional Mao suit—a left-hand pocket held a Western-style polka-dotted pocket square, for example, and the suit had only three pockets versus the traditional four.

But those hoping for a Xi-Obama fashion face-off comparable to the one earlier last week between the wives of two leaders were disappointed. By Monday, Mr. Xi had returned to the standard black Western suit and maroon tie in a meeting with U.S. President Barack Obama on the sidelines of the security summit.

One Weibo user who praised Mr. Xi’s Chinese-style suit nonetheless said he wouldn’t mind if Mr. Xi decided to stick to the usual script in Europe.

“It’s OK to wear a Western-style suit as well,” the user wrote. “When in Rome, do as the Romans do.”